What Is Death - Tyler Volk
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gerous, and if, afterwards, it had been explained to me what I should have done, I might not even have understood why lack of reaction was inappropriate.
When they want to point out the powers of our unconscious, cognitive scientists look to everyday, simple speech. Somehow we talk and it all comes out fairly coherently. Yet so little is thought out beforehand. There are impulses of meaning, perhaps faint flashes of imagery in our thoughts, and then sentences tumble forth. And what makes these impulses, the flashes of intent that precede sentences, except the unconscious as well!
Perhaps you would like more conscious control over the cognitive unconscious, but we with our inadequate consciousness are far too puny for that. A striking proof of the limitations of consciousness has been provided by the cognitive scientist Bernard Baars, in an exercise that anyone can do.7 Put down a list of numbers, such as 114723. Then try to keep them in mind while you read again the preceding paragraph with comprehension, pretending that you might be asked at any moment for this list of numbers. If you are like me, you can do either one or the other but not both. Keeping the list actively in mind turns the writing into gobbledygook. On the other hand, reading with attention to the meaning of the words pretty much dissolves the list of digits. Given the same reading task with only one or two digits to manage, the numbers can probably be maintained. But shouldering a slightly more complex list such as the one above maximizes our so-called working memory, from which consciousness draws in real time. In comparison to this small capacity, our unconscious could hold a vast library of volumes and analyze them.
The powers of the cognitive unconscious, such as those of the amygdalas, for example, are working all the time. Silently, thanklessly monitoring signals, always a step ahead of the conscious mind, their skilled efforts have served me in crucial situations. Every object I see or hear is being evaluated.
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Is it a friend or dangerous foe that must immediately be reacted to? Imagine having to consciously listen carefully enough to each sound you hear to classify it as fearful or not. It could be done, perhaps. But that would be all you do. With the aid of the amygdalas and many other structures and pathways in the brain, the entirety of the unconscious rolls along as a thunderstorm, compared to that one raindrop of conscious activity.
Gabriele Rico calls our brain “the three-pound miracle between our ears,”8 and for all its hyperbole, that might still be an understatement.
Consider just the pathways for separating objects, say, a glass of water, into “what” and “where.” From our eyes neuron circuits converge to the thalami and then diverge to regions in the rear of the head. From these primary vision processing regions, which are functionally devoted to a variety of tasks, such as creating color, size, and shape, two major paths feed the signals to more forward parts of the brain. The higher path goes to brain regions used in knowing where something is, which we need in reaching for that glass. The lower path, which goes into the amygdala as well as other brain regions, is used for the many tasks in which we need to know what an object is. Seems simple, but something in our brains performs this.
The differences in brain parts used for distinguishing types of objects is truly amazing. Knowing what an object is requires not just forward pathways of signals from the primary visual zones in the brain’s rear but comparisons of the signals with what we know already. What do we know? That a hammer is a hammer and a dog a dog. Remarkably, brain scientists have found that the recognition of tools and animals is handled by different parts of the brain.
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It had been previously known that one patient with brain damage might be deficient in naming animals when presented with pictures of creatures, while another patient had problems only with man-made objects. But now with modern techniques that record what regions of the brain are active when ordinary test subjects are performing specified tasks, the separate processing of animals and tools can be more precisely mapped.9 During experiments, either task of naming pictures of animals or tools activated certain areas associated with speech. But the animal task also selectively stimulated a particular region on the brain’s left side way in the back, a region involved with some of the earliest stages of visual processing. Naming tools selectively activated a region on the left side somewhat above the ear, a region known to also be activated when imagining hand movements. In addition the tool task fired up a region used to generate action words.
Brain-damaged patients have been found with problems producing vowels, but were normal with speaking consonants.10 The inverse problem has been found in other patients. It thus appears that our brains separately process these two basic components of speech in different regions, at least in part. Furthermore, regarding sounds, a special brain region shows greater sensitivity to vocal sounds as compared with all other types of environmental sounds.11 Many of these separations of function make sense because they reflect useful distinctions in our world. We need to know both what and where to take action. Special attunement to human voices seems very advantageous from an evolutionary viewpoint.
New technologies have allowed researchers to point out the active regions of subjects’ brains and analyze even more complex mental activities. One recent example involved subjects who kept a main goal in mind while performing tasks toward secondary goals.12 The experiments showed that
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certain regions in the front of the brain were active only then. These regions were not engaged with only either main or secondary goals performed by the subjects (who sought patterns, in this case, in sequences of alphabet letters). Researchers claimed that mental activity with both main and secondary goals alone is the essence of planning and reasoning, which perhaps is made possible by certain regions of our brains.
What about memory, such as that of personal experiences? A centralized part of the brain, shaped like a seahorse and called the hippocampus, is vital for this. In one case, a man whose hippocampus was damaged as a result of encephalitis could recall his neighbor as a child but, after the injury, nothing about where he currently lived.13
What about this thing called the self? Is it just the integration of everything in the brain? Or is the self specialized within the brain? Of course this all depends on what is meant by the self, and in the words of one brain research group, “there is no coherent body of knowledge that comprises a cognitive neuroscience of self.”14 I have examined endless pages from neurobiologists and philosophers who are not even able to agree on how to define the self. Neither can anyone be definite about the terms “mind” or “consciousness.” All these—“self,” “mind,” “consciousness”—are employed in various ways by various people at various times. The terms more or less overlap, depending on speaker and circumstances. Yet we can say they all refer to something intrinsic to our brains. They are words we use to point out to ourselves, in our inner dialogues, something quintessential about who we are and how we operate in daily existence.
Despite difficulties with definitions, specific investigations have begun to shed light on aspects of the self. The above-noted research group claims, for example, that a variety of “self-processes,” such as autobiograph-
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ical memory and evaluating whether a picture of a face is of oneself or not, occur preferentially on the right side of the brain.
Some key experiments were conducted with patients who were undergoing anesthetization of either the left or right sides of their brains.15 Surgeons needed to know about each patient’s degree of hemispheric dominance prior to surgery to treat epilepsy. Brain researchers used this opportunity to test for the neural location of self-recognition. They showed pictures of faces to the halfanesthetized patients. These faces had been computer-generated as morphs between a subject’s own face and a famous face. A woman might see a blended face that was halfway hers in its features and halfway that of Marilyn Monroe. Upon recovery from the anesthesia, the same patients were shown individual pictures of both themselves and the famous person, and they had to choose which one they thought they had seen earlier when half their brain was numbed. Patients who saw the morphed face while the right side was numb picked the famous face as the one they had seen. Patients recovering from leftbrain anesthesia picked their own face as the one they saw during the numbing. After these experiments and a review of other findings, the researchers concluded, “It is conceivable that a right-hemisphere network gives rise to selfawareness, which may be a hallmark of higher-order consciousness.”
No doubt the self is a complicated psychological concept, encompassing both conscious and unconscious parts of our daily existence. But we have little trouble pointing to ongoing daily experience of consciousness: the contents of our moment-to-moment “field” of awareness, which encompasses both objects of our senses and the inner feelings, imaginings, and
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silent dialogues that take place in our heads. To a large degree consciousness is us, and inroads here as well have been made by neuroscientists that indicate consciousness is surely brain-based.
Referring to consciousness, neurobiologists Gerald Edelman and Giulio Tononi state, “On the basis of studies of lesions and stimulation, we are confident that, for example, the activity of certain brain regions, such as the cerebral cortex and thalamus, is more important than the activity of other regions.”16 A standard illustration of this is the fact that if half of the brain is removed, which is done in some desperate situations of disease, the recovering person might experience cognitive problems but will still possess consciousness. In contrast, remove a couple key areas of brain and consciousness will be lost, even though the person remains alive.
Bernard Baars, a cognitive scientist, has summarized some of these key parts of the brain, which specifically function to make consciousness.17
One is the reticular activating system, or simply reticular formation. Located in the brain stem, it is shaped like a narrow, squat funnel under the brain’s somewhat slumped sphere. According to researchers Blair Turner and Margaret Knapp, “The function of this system is associated with arousal, and its destruction produces permanent coma.”18 This arousal is not the kind encouraged in you by an eager lover. The term in neurobiology refers to the fact that the reticular formation makes the rest of the brain sensitive and awake. Remove or damage the reticular formation and consciousness ends.
Baars points to another important brain organ, the thalamus. Each of the two thalami is an egg-sized “mini-brain within a brain,” located about an inch above the reticular formation. We have already seen how each transfers signals from the ear to the nearby amygdala. In fact, each is a central relay station. The thalamic eggs connect with virtually every
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portion of the brain that involves sensations, motor commands, attention, and other aspects of cognition.
Scoop out a couple egg-sized spoonfuls from the top of the brain and a person might suffer a few problems, perhaps in willing some part of the body to move. But full consciousness remains. On the other hand, take out or damage the two thalami, which total only about five percent of the brain, and consciousness collapses. A person would then enter what is called a persistent vegetative state. An example was Karen Ann Quinlan, the young woman whose lack of consciousness while she remained alive for nine years in a persistent vegetative state spurred the development of many new legal and medical guidelines. Upon death, when her brain was autopsied, the most significant damage was found in her thalami.19
It might even turn out that not the full thalamus but crucial parts of it are the key. Within each thalamus, in between folds of tissue called laminae, are several structures the size of pencil erasers: thalamic intralaminar nuclei. So pervasive are the connections between these nuclei and the brain’s surrounding, large cortex that the special nuclei have been compared to a spider in its web. Referring to the nuclei, Baars states: “Aside from the reticular formation, this is the only part of the brain that seems indispensable for waking consciousness.”20
Consciousness requires contents that include sensations, thoughts, images, and feelings, and this complexity of components implies the presence of a network of processes within the brain, not just any specific structural part, as important as certain parts might be. For example, Edelman and Tononi point to how the thalami and the cortex are connected. Structurally, the cortex is like a fat baseball glove that surrounds the thalamic eggs. In the words of these researchers, “Consciousness is a dynamic property of a special kind of morphology—the reentrant meshwork of the thalamocortical system—as it
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interacts with the environment.”21 Their system refers to thalamus, cortex, and internal connections, which the researchers call “reentrant.” This term means that wherever a region in the cortex connects to a region in the thalamus, then the same region of the thalamus connects directly back to the region of origin in the cortex.
The special morphology of reentry produces the ongoing series of unique states we experience as our conscious minds, an integration that Edelman and Tononi call the “dynamic core.” The dynamic core is like a tangled network of central springs with more peripheral springs. Disturbing the peripheral springs can set the entire central core vibrating. The dynamic core both changes all the time and maintains a certain constancy, somewhat like a flame, flickering in endless variation yet still located at the wick of the candle. Consciousness might be seen as a vibrating flame in the brain.
And death would be its snuffer. When the brain’s activity ceases, consciousness must also cease.
Here is the rub: If our brain is the source of self, the main arbiter of our senses, the pilot for our bodies when we have no time to think for ourselves, the source of daily consciousness, then how could we live without it? How could we have a self once the brain has been denied us by death? How could we sense the glories of heaven or the pains of hell without a brain to process them? How could we enjoy any mental capacity at all? Thus with all the discoveries about the brain flooding the technical journals, it is clear we cannot possess a soul. After death, there can be no reincarnation of self because the self is forever tethered to the body it was developed within after birth; it cannot go somewhere else and wait to enter a new body some time in the future. There can be no eternity in any heaven or hell, no purgatory, no bardo states. If you want to find nirvana, then you have to look for it here.
W E L I V E I N
T W O D I F F E R E N T
W O R L D S
hat would we be when we die, without the living brain?
WWe could not talk, or distinguish tools and animals, or reach for a glass in some otherworldly place. Life in heaven is often portrayed as an idealized version of life here in the material world. In heaven, people communicate to each other, they often have something like bodies made of spirit, and they see each other. But how could people in heaven recognize each other without a brain that has special circuits for processing individual faces? How could they talk without a brain to store, select, and order words? After death we could neither plan nor reason. We would be unable to form new memories. So what would we be? Following this line of logic, I cannot help but believe that we terminate as individual psychological beings at the moment of bodily death.
Some of you may feel the same way, and I’m sure some of you do not. To distinguish these two camps I’d like to propose some terms. I’ll use “monists” for those who believe that there is a oneness of brain and self, that
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together they form a single system, indivisible by death. “Dualists,” on the other hand, see the brain and at least some aspect of the mind as independent entities detached at death. This aspect is sometimes called the soul, personal spirit, interpersonal spirit, or atman—hundreds of names could be found in the anthropological literature of world cultures. Whatever the word, dualists accept both this plane of earthly reality and another very different plane—of astral existence, nonmaterial spiritual beings, angels, formerly alive people, disembodied souls. Whereas monists accept just the former.
Dualists could point to the difficulties science has in explaining consciousness. This is true. Until recently, it was not even considered scientific to investigate consciousness because such studies always seem to depend ultimately on a large dose of subjectivity: namely, data must come from what people report they experience. How can these reports be verified? By studying the effects of different types of brain damage and considering the data from the latest generations of scanning technologies, a foundation for a science of consciousness is being laid, but there is still a long way to go. Antonio Damasio, one of the looming figures in the science of consciousness, has recently written, “Not only is it true that we have not yet exhausted the possibilities of explaining consciousness in neuroscientific terms, but it is also true that we have barely scratched the surface of neuroscience in terms of such an attempt.”22 Yet scratching the surface in this case is quite the something. And what we do know indicates that consciousness is brain-based, strengthening the case for monism.
For many dualists the logical bottom line is not any counter to the findings of neurobiology but the fact that they often base their beliefs on personal experience. In working on this book, I have found there’s nothing like the topic of death to take conversations with friends and relatives straight to